I am a dental hygienist and I recommend the new Oral B Triumph. I like the Oral B over the Sonicare because the smaller brush head allows for better tooth and gum cleaning. It has different cleaning settings, regular, sensitive and polishing. It's also got a timer so you're sure to brush for the recommended two minutes. It's pricey, about $139 but worth it. Hope that helps.
I am partial to Oral-B's electronic toothbrush line. I specifically use Oral-B Triumph. It's got different settings, including a setting that massages the gums. It also has a 2:00 minute timer that vibrates every 30 seconds so you can know when to switch to another quadrant in your mouth.
I don't know which one's best, but I think usually the OralB ones are considered very good.
You should brush for at least two minutes twice a day, as the brushing helps remove plaque. Use a soft brush so that you don't hurt yourself with too vigorous brushing.
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